I have an 11/87 SP. I had a gunsmith drill and tap the receiver for a leupold base. I have had nothing but trouble keeping the base screws tight. The two front holes are drilled and tapped through the receiver and into the barrel shroud, and these are the most troublesome. Could I be getting movement from the barrel? Could this be the problem? Really could use some advice. Thanks, Smoker1

most remingtons are thin along the top of the receiver not much meat for the threads.
the rem express is a lot thicker and can be drilled and tapped for scope.
Remington came out with a cantilevr barrel that works for mounting scopes, with long eye relief. the red dots work best for me.
Dave

First remove the screws and throughly clean the threads on the screws and the threads in the receiver with alcohol moistened pipe cleaners and then blow them clean and dry with compressed air.

When you reassemble them place a very tiny [!] amount of good high viscosity oil on the threads and torque them to 10 to 15 inch pounds or so.

Thanks for the info folks. Appreciate it. This is the third iteration of the loose screw syndrom. I have used a mild Loctite thread locker, which came loose. This time I'm using a very high strength loctite. I disassembled the barrel and found a very light burr on top of the threaded holes, which I filed smooth. Then used brake cleaner on all the surfaces paying strict attention to the threaded holes both in the receiver and the barrel. It's been 24 hours for a good cure and if the weather here will permit I'll go out today. Smoker1

"Through the receiver and into the barrel shroud...." Are you kidding? What in the hell was the man thinking?

Must have worked...last two went into ~2" @100. Happy with that. Smoker1

Why not just use shorter screws?